There were no jobs in the cities.
grow in car sales
The automobile industry. In particular public transportation (the diesel engine).
Widespread availability of automobiles.
New Railroad lines :)
The growth of suburbs offered many opportunities for business owenrs
One reason for the growth of suburbs was increased automobile ownership and improved transportation infrastructure.
The growth of suburbs caused many new types of business to do well. Apex
the growth of suburbs encouraged innovation in business (apex)
There were no jobs in the cities.
Improvements in transportation
There were no jobs in the cities.
The growth of malls and supermarkets (apex)
The one thing that helped to spurn the growth of the suburbs was the need for laborers to support factory operations, which were located in urban areas.
grow in car sales
This is not a question, but a statement. Rewrite a question.
The growth of malls and supermarkets (apex)